Skeletal Radiology最新文献

Over the past decades, the growing pursuit of the "ideal body" has increased the demand for aesthetic procedures. There are four main types of procedures: autologous fat grafting, gluteal implants, dermal fillers, and local flaps. Fat grafting is the most commonly performed with the lowest complication rates, while implants are associated with higher risks. The use of dermal flaps is generally restricted to patients with massive weight loss, as in bariatric surgeries. Dermal fillers are not recommended by the Food and Drug Administration (FDA) for use on the buttocks; however, they have been increasingly used, especially by unqualified professionals. Complications include infections, seromas, hematomas, and suture dehiscence; however, the most feared complication is pulmonary embolism, more related to fat grafting and filling substances. Given the rising number of postoperative magnetic resonance imaging (MRI) exams, more and more radiologists have come across aesthetic gluteoplasty exams in daily practice and must understand the anatomy and the main anatomical variations of the gluteal region. Besides, it is important to have knowledge of the surgical techniques employed and actively look for potential postoperative complications related to each type of procedure. This article reviews surgical techniques, anatomical considerations, expected MRI findings, and common complications after gluteoplasty.

Objective: This study was aimed at identifying MRI findings related to total hip arthroplasty (THAs) infection using coronal STIR with metal artifact reduction sequences (MARS) at 1.5 T.

Materials and methods: This retrospective multicenter study included all patients with THAs who underwent 1.5 T MRI with MARS from December 2015 to April 2020. Two groups are as follows: an infected group and a non-infected group (including asymptomatic THAs and symptomatic non-infected THAs). MARS were either multi-acquisition with variable-resonance image combination (MAVRIC) or slice encoding for metal artifact correction (SEMAC). Imaging features were evaluated to assess their association with THA infection (including both symptomatic and asymptomatic patients). Sensitivity, specificity, and accuracy of these imaging findings were assessed, and inter-reader agreement (kappa, K) was determined.

Results: Sixteen patients with THAs had periprosthetic infection, compared with 46 THAs in the non-infected group. Bone edema extending to adjacent soft tissues, defined as a combination of femoral bone marrow edema, hyperintense cortical signal, periostitis, and overall soft tissue edema, had the greatest diagnostic performance for infection: 15/16(94%) infected THAs and 0/46(0%) non-infected THAs (accuracy = 0.98, sensitivity = 0.94, specificity = 1, p < 0.001 Chi-Square test). This combination, predominant in the infected group (p < 0.001 for all), also demonstrated separately high accuracy (acc = 0.94-1), sensitivity (se = 0.94-1), and specificity (0.94-1). Fistula and fluid collection were highly specific (spe = 1) and accurate (acc = 0.81-0.82), although less sensitive (se = 0.25-0.31, p < 0.001).

Conclusion: The combination of femoral bone marrow edema, hyperintense cortical signal, periostitis, and soft tissue edema is accurate in the diagnosis of periprosthetic hip joint infection using coronal STIR with MARs at 1.5 T.

Objectives: To evaluate whether a dedicated, anatomically realistic knee phantom with orthopedic implants can be used to optimize clinical MRI sequences under realistic metallic conditions and to assess whether phantom-optimized sequences improve image quality compared with routine protocols.

Materials and methods: A 3D-printed knee phantom integrating a titanium screw and a stainless-steel fixation plate was developed. Phantom imaging was performed on a clinical 1.5 T MRI system. In this exploratory proof-of-concept study, T1w and STIR sequences were iteratively optimized using the phantom and compared with vendor-default and routine clinical protocols. The phantom-optimized sequences were subsequently applied in three asymptomatic volunteers with metallic knee implants and compared with routine sequences. Image quality was independently assessed by four blinded readers using a 5-point Likert scale across spatial resolution, artifact reduction, and overall image quality.

Results: Phantom-optimized sequences achieved significantly higher image quality scores compared with routine protocols. Improvements were consistent across all three predefined criteria: spatial resolution (mean increase +0.70 points, p < 0.001), artifact reduction (+0.65, p < 0.001), and overall image quality (+0.78, p < 0.001). These gains were observed for both T1-weighted and STIR acquisitions without extending acquisition times.

Conclusion: Phantom-guided optimization provides a reproducible, patient-independent framework for tuning MRI protocols near orthopedic hardware. Anatomically realistic phantoms represent a promising methodological tool for developing, testing, and standardizing MRI sequences under controlled and clinically relevant conditions.

Purpose: The aim of this study is to evaluate the treatment response of patients with osteoid osteoma (OO) following radiofrequency ablation (RFA) and identify factors influencing the time to complete pain relief post-treatment.

Materials and methods: This is a retrospective cohort study of patients who underwent RFA for OO between 2010 and 2023. Demographic, clinical data, and time between symptoms onset to diagnosis and RFA were recorded. CTs were reviewed for OO location (upper extremity, lower extremity, spine/pelvis), intra-articular versus extra-articular lesions, nidus size, degree of peripheral bone formation, and presence of vessel sign. Procedural related information included needle approach, RFA active tip length, and number of RFA cycles. Statistical analysis was made on factors and their correlation to complete pain relief.

Results: Out of 63 patients included in our study (mean age 19.3 ± 10.6), OO were located in the upper extremity (n = 7, 11%), lower extremity (n = 48, 76%), and pelvis/spine (n = 8, 13%). OO in the pelvis/spine achieved the quickest complete pain relief (14 days) compared to those in lower (25 days, 11 days longer) and upper extremity (54 days, 40 days longer) respectively (p = 0.04). Vessel sign had significant association with shorter time to complete pain relief (p = 0.03). Longer duration of symptoms until diagnosis or RFA, larger nidus, more bone formation, and extra-articular OO responded slower to RFA, though statistical significance was not reached.

Conclusions: Anatomical location and certain imaging characteristics of OO may have association with time to complete pain relief following RFA. The findings can potentially help optimizing patient counseling with more realistic expectations and symptom management strategies prior to and following RFA.

Many of the tissues of interest in the evaluation of the knee by magnetic resonance imaging (MRI), including subchondral bone, deep calcified layer of cartilage, menisci, tendons, and ligaments, have very short transverse (T2 and T2*) relaxation times related to their intrinsic structure. These tissues appear anechoic on conventional MRI sequences as signal has already decayed to its minimum when image acquisition begins. Only in the setting of significant injury or degeneration is there detectable signal on conventional MRI sequences. Ultrashort echo time (UTE) MRI, which allows for the qualitative and quantitative assessment of short T2 tissues in their normal states, offers a unique opportunity to detect and intervene upon pathological changes early to prevent irreversible damage. Changes on UTE-T2* imaging allow for the identification of subtle alterations in collagen structure, hydration status, and mineralization of tissues that precede morphologic changes visible on conventional imaging. Early detection of such microstructural changes can allow for the earlier diagnosis of tendinopathy, meniscal injury or degeneration, and early osteoarthritis, potentially allowing for improved patient outcomes through earlier intervention. This review will focus specifically on the clinical applications of one UTE MRI technique, UTE-T2*, in the evaluation of musculoskeletal tissues about the knee.

Sports-related knee injuries are common and clinically consequential. Interpreting MR imaging through a biomechanical lens links injury patterns to the forces that produced them, improving the detection of subtle but prognostically important lesions. Characteristic osseous findings-contusions, subchondral/osteochondral fractures, and avulsions-act as "maps" of force vectors that distinguish compression from distraction mechanisms. In anterior cruciate ligament (ACL) trauma, bone bruise locations have kinematic associations (i.e., valgus-flexion-external rotation vs varus-flexion-internal rotation) and enable a targeted search for injuries involving functionally related structures, such as the menisci. The medial meniscus functions as a secondary stabilizer to anterior tibial translation. Therefore, peripheral vertical longitudinal tears and meniscocapsular ramp lesions are frequent companions of ACL rupture and may be overlooked without a mechanism-based approach. The lateral meniscus is vulnerable to radial/posterior root and peripheral capsular injuries during translational and compressive loading of the lateral compartment. Posterolateral corner structures resist varus and external rotation forces; unrecognized PLC injury compromises cruciate reconstruction and perpetuates rotatory instability. This review synthesizes biomechanical principles to provide a practical, pathophysiological framework for MRI interpretation and reporting. Applying this approach enhances diagnostic accuracy, guides surgical decision-making, and supports better outcomes for athletes with acute knee trauma. KEY POINTS: • Biomechanical principles provide a systematic framework for interpreting knee MRI after sports trauma, improving diagnostic accuracy and detection of subtle lesions. • Characteristic injury patterns on MRI often reveal the underlying traumatic mechanism, directing targeted evaluation of osseous structures, ligaments, tendons, and menisci. • Subtle injuries such as Segond fracture, ramp lesion, or posterolateral corner disruption may be overlooked without a mechanism-based interpretive approach.

Older men suffer from hip FFx (fragility fracture) at femoral neck T-score approximately 0.6 higher than older women, thus we proposed a new category of low BMD status, osteofrailia, for older Caucasian men with femoral neck T-score ≤ -2.0 (T-score ≤ -2.1 for older East Asian men) who have an increased risk of hip FFx. Around the age of 78 years, mean LS (lumbar spine) QCT BMD is around 68 mg/mL and 100 mg/mL for East Asian men and Caucasian men, respectively. For East Asian men, LS QCT BMD <68 mg/mL offers a sensitivity of 77% for detecting vertebral FFx cases, which is consistent with LS QCT BMD <80 mg/mL and < 50 mg/mL offering a vertebral FFx detection sensitivity of around 77% for Caucasian women and East Asian women, respectively. For Chinese men, T-score ≤ -2.5 predicts hip FFx risk better than other T-score values, and LS DXA T-score - 2.5 corresponds to QCT BMD 68 mg/mL. Hip FFx occur at approximately 0.5 LS T-score higher in Caucasian men than in Caucasian women. Among older Caucasian populations, for the separation of patients with FFx and without FFx, QCT BMD <100 mg/mL in older men is approximately comparable to <80 mg/mL in older women. For FFx risk prediction, we propose osteofrailia threshold LS DXA T-score to be ≤ - 2.5 and ≤ -2.0, and QCT BMD to be <68 mg/mL and < 100 mg/mL, respectively, for East Asian men and Caucasian men. The relationship between LS QCT BMD and hip FFx risk should be better investigated in the future.

Blastic plasmacytoid dendritic cell neoplasm is a rare, aggressive hematologic malignancy that commonly involves the skin and can rapidly disseminate. We report the case of a 58-year-old man presenting with a rapidly enlarging reddish nodule over the right scapular region, which grew from 9 to 20 cm within 1 month. Chest magnetic resonance imaging revealed marked dermal thickening with a band-like low signal on T2-weighted images ("T2-dark band"). The T2-dark dermal layer was interposed between the tumor exhibiting restricted diffusion-superficial components bulging outward and invasive subcutaneous components (the "Hamburger Sign"). ¹⁸F-FDG PET/CT demonstrated intense uptake (SUVmax, 17) in the cutaneous lesion and revealed the involvement of multiple skeletal sites. Histopathology revealed diffuse infiltration of atypical cells extending from the dermis into the subcutis. Immunohistochemistry was positive for TCF4, CD123, and TCL1, confirming the diagnosis. Radiologic-pathologic correlation suggested that the T2-dark dermal band reflects interstitial tumor infiltration that splays and preserves dermal collagen bundles, providing a basis for the T2 shortening in a collagen-rich, low-free-water layer. We propose the "Hamburger Sign" to describe characteristic imaging findings of the blastic plasmacytoid dendritic cell neoplasm, that is, the dermal T2-dark "patty" is sandwiched by tumor "buns" and the superficial and deep tumor components. Early recognition of this sign may prompt appropriate immunohistochemical work-up (plasmacytoid dendritic markers of TCF4, CD123, and TCL1) and expedite diagnosis, particularly when initial biopsy suggests undifferentiated carcinoma.

Objective: We assessed whether preoperative advanced multisegmental degeneration is associated with worse 1-year outcomes of primary single-level lumbar discectomy.

Materials and methods: A literature-based scoring system was developed to quantify degeneration in the operated and adjacent lumbar segments, based on advanced phenotypes of common intervertebral disc-related degenerative features. Each segment received a score from 0 to 3: cranial and caudal ≥ 25% endplate damage (EPD) and Modic changes type I (MC1) were assigned 0.5 points each, and Pfirrmann grade ≥ 4 was assigned 1 point. The final adjacent segment degeneration score was calculated as the mean of the operated and adjacent segment scores. Prospectively collected data from primary single-level lumbar discectomy patients operated in a single center between 2017 and 2022 were retrospectively analyzed. Patients were stratified into none-to-mild (≤ 0.5), moderate (0.5 < score < 1.33), and severe (≥ 1.33) degeneration groups, using the 40th and 80th percentile cut-offs. A linear mixed-effects model was employed to assess between-group differences in 1-year improvements in low back (LBP) and leg pain (VAS, 0-100), disability (ODI), and quality of life (EQ-5D-3L).

Results: Among the 140 patients included (mean age 45.3 years; 57.9% male), all PROMs improved overall. The severe group showed significantly smaller improvements from baseline to 1-year follow-up, with adjusted mean differences in change of 20.2 for LBP, 31.6 for leg pain, and 11.1 for disability relative to the none-to-mild reference group.

Conclusion: Severe preoperative adjacent segment degeneration may be associated with smaller 1-year improvements in pain and disability after primary single-level lumbar discectomy.